And Dust there are a number of non-standard installations with a lot of trouble free hours of operation, burning cheaper fuel, and costing less to operate.

Cost: - Non-standard engines cost a fraction of what a certified engine does. Add to that that you can overhaul a non-cert for years and still pay less for maintenance than one overhaul of a cert would cost.

Operations: - I think to use of the word "all" applies here. All non-standard engines run on cheaper or readily available fuels. If you are paying a $1/gal less than avgas that's a lot of savings each fillup. Granted, you should remember not fly at higher altitudes mogas.

mmmmmmmmm - initial cost is a toss up - used engines can be found with allot of life in them and all accessories for a comparable cost to a non standard engine.

the cost savings are definitely at the rebuild time, cost savings on fuel, to me are iffy as mogas is not readily available across the country where you may want to fly.

that said - the reason for my post is to remind the new to aviation that we have here - the engine is not hard and there are little or no teething on standard airplane installations.